1. Field of the Invention:
The present invention relates to a novel aqueous cold setting paint which is preferably used as paints for outer parts, iron constructions and concretes.
2. Description of the Prior Arts:
The cold setting paints used for these usages can be classified to solvent type paints and aqueous type paints. The solvent type paints have been mainly used. However, it has been required to use the aqueous type paints instead of the solvent type paints from the viewpoints of environmental problem, fire, labour safety and hygiene problems.
The aqueous type paints are further subclassified to emulsion type paints, microemulsion type paints and water soluble type paints.
The emulsion type paints have been widely used in practice. However, the emulsion type paints have inferior to the conventional solvent type paints since the water resistance and the durability are disadvantageously low.
The water soluble type paints can not be replaced to the conventional solvent type paints since the water resistance, the durability and the weathering resistance are remarkably low.
The microemulsion type paints have been developed but they can not be replaced to the conventional solvent type paints since the chemical resistance and the weathering resistance are still inferior in the present technical level.
There have been many paints which are hardened by a heating or a radiation. Various processes for preparing these type paints have been known. However, it has been rare to obtain an aqueous cold setting paint.
Processes for preparing emulsions of vinyl type polymers with an emulsifier of a maleinized polybutadiene have been disclosed in Japanese Pat. Publication No. 43381/1974 and Japanese Unexamined Pat. Publications Nos. 73488/1973 and 34683/1972. However, the emulsions obtained by these processes have disadvantages of inferior alkali resistance and weathering resistance.
Aqueous compositions containing a drying oil, a semidrying oil and an unsaturated aliphatic acid or a derivative thereof or processes for preparing the compositions have been disclosed in Japanese Pat. Nos. 32414/1972, 4214/1975 and 18503/1975. However, the compositions obtained by these processes have disadvantages of inferior alkali resistance and weathering resistance.
In order to overcome these disadvantages, the inventors have studied and found that aqueous paints prepared by admixing a specific acryl type copolymer with a water soluble epoxy resin have excellent solvent resistance, weathering resistance, chemical resistance, water resistance, adhesiveness, processibility and economical advantage.
The inventors have further studied to improve these aqueous paints and have found that aqueous paints comprising a specific copolymer and an alcoholic solvent soluble epoxy resin impart superior water resistance. The present invention has been attained by the finding.